Step 1: Step 1: Finding Your Base

Because of the use of fire cement the initial base doesn't have to withstand the same temperatures that the forge will produce. However a steel base is preferable as heat will still be transferred to the base.for this try to use a steel base with a bowl like shape (the one we created is our first and smaller to allow us to understand how the materials work on a smaller scale). This base will be holding the coals through a layer of fire cement.

After this prepare the base by cleaning the surfaces the cement will come in contact with to ensure that the cement will fix to the surface.

Step 2: Step 2: Create the Airflow

For this fix the base in place and use a center punch in the center to help guide the drill bit, after this drill the base to create a hole smaller than the internal diameter of your Elbow piece. Next force the elbow to be threaded to bring more strength to the joint.

This will be reinforced later by the fire cement, also note that we have used a brass elbow and copper pipes, while the melting points of both of these metals are below the created temperatures they are safe from melting. This is due to both the fact that the temperature of the coals will be mainly directed upwards and that we will be reinforcing these pieces with more fire cement.

Step 3: Step 3: Connecting the Elbow to the Pipe

This pipe will supplying the coals with high pressured air which creates the high temperatures which can soften metals. In this case the elbow is connected to the copper pipe via a compression fitting. the pipe then leads to a safe distance where is connected to a air pump via an adapter for blowing up air beds (however we have found that the airbed pumps don't produce the temperatures that we are looking for and i would advise to look for a stronger system such as a leaf blower)

Step 4: Step 4: Applying the Fire Cement

The fire cement we used EverBuild which can withstand temperatures up to 1250C which means that the forge is not equipped to work with steel as the melting temperature is too strong for the cement.

The cement was applied to the base of the bowl and sides, the sides being 1 inch thick and the base 0.5 inches thick. Note that the cement will have a window of time in which it is malleable, EverBuild being 4 hours.

Step 5: Step 5: Firing the Forge

Now that the cement has finished setting, fill with coals and allow them for burn for some time before increasing the pressure of the air, after you have had the coals burn with the blower on let the coals cool down for 1-2 hours and inspect the cement, elbow and pipe for signs of stress from the temperatures. We found this setup to both provide us with enough to melt aluminium cans within 5 seconds while maintaining the structure of the forge.

Step 6: Finished

Looking back at this project we would have loved to choose a base with higher sides or a deeper bowl to focus the temperature more efficiently, as well as this we would also mount the forge on top of something so that we could use it without having to hunch down.

Another improvement in which we would introduce in any future forges would be a cap over the top of the airflow to stop coals from breaking down and falling into it, this could be as simple as small clay pot with drilled holes to disperse the air.

This is our first/prototype forge to test the mechanics before committing to a bigger operation.

Remember that that the best way to put out a fire at these temperatures is a bucket of sand, water may cause the molten metals to spit which is never fun so make sure you have sand available as well as a leather apron and face protections!

We also realise that this is our first attempt at this, and accept that both our forge and this instructable is far from perfect. We would love to here constructive criticism and take it on board =)

Thank you for reading and we hope everything works out within your project!

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8 Discussions

spot on! I saw a good workshop pot belly out of brake drums also. They scale up in size too, the author was looking for a bigger bowl and a tractor or truck brake drum could work, would need a decent plate across the inner circumference. I saw a handy fire bowl out of the bottom half of stainless steel keg too (was not a forge though).

The air mattress air pump will put enough air out if you enlarge the pipe to atleast one inch. I had an electric blower on one forge with a 3" water heater flue pipe feeding to a galvanized 3" "T". The "T" was set in so that it was a straight thru from the fire box down for clunkers to fall out, the flue pipe was then attached to the "leg" of the "T". Oh I did forget to tell you the was a 3" ball valve between the "T" and the flue pipe used to regulate the air going to the firebox since the blower was a constent speed blower. This forge worked great for home use, it had side walls and a flue funnel on top to hook up to a chimney in desired. AT the same time I also had a rivet forge with a hand cranked blower i used for shows do to portablity of it.. Electric forge was 32"x32" square table where as the rivet was maybe 18" in diameter.

I made something like this a few months ago out of an old Home Depot fire pit. First of all I would encourage everyone attempting to make a forge to check out the modern blacksmiths brazzle mini forge first. I would critique this design in saying that a copper pipe will not allow enough air flow. Also, you can simply line the bottom of your forge with some sand, allowing enough insulation to actually get up to forging temperature simply running on wood.

Thanks, mrwaffleeyes. I'm salvaging an old, metal, roll around fireplace with a hemispheric bottom. I'd like to line the bottom of mine with some pumice rock tiles fashioned from a broken lava rock fountain my wife got from her grand mother. Would the fire cement work as a fixative for the pumice tiles? I don't intend using it as mortar between the tiles. My intention is to use such a furnace for case color hardening of steel. Stay tuned for pix.

We use it for melting Aluminium to a molten liquid, however the maximum (safe) temperature that the cement states that it can resist is 1250 degrees Centigrade which in theory can melt wrought iron or cast iron however I have not tried it yet. The upper range of the temperatures may also be able to heat the desired metal (such as steels which melt above 1250) to a "cherry hot" temperature which would allow you to hammer the metal into a new shape. =) i hope this helps and i have not used any ferrous metals on this forge as of yet so i wouldnt be able to give you a 100% on its capabilities and saftey.

Back in HS I did something like this. Mother's vacuum, hose (blower side) to a beer bottle (bottom broken off) into the base of a coffee can, angled, (hole punched) and the can/bottle/hose end buried in the ground. Paper in, kindling, match - vacuum on for 1 sec, more kindling, vacuum on for 2 sec, add coal, vac for 3.... 4.... 7.... 10... more coal, vac on.......... more coal. At full boil it took 30 second to vaporize 3 inches of 3/4 rebar. Today I'd prob. use a hair dryer - would cut the temp down to white hot no vaporize....